The calculated distance (air line) between Dĩ An and Thủ Dầu Một is approximately 9 miles respectively 15 kilometers.
By car or train, the actual journey to Thủ Dầu Một is certainly longer, as only the direct route (as the crow flies) between Dĩ An and Thủ Dầu Một has been calculated here.
Air line (approximately)
15 kilometers
8 nautical miles